Two surfaces reach the dialog: the fillSeries command, which infers the template and both
directions from the selection, and the fill menu's Series…, where a drag has already said which
cells are read, which are covered and which way — so only that direction is offered. Both hand the
criteria over here and share everything else: the context the dialog asks its questions of, and
what happens when it answers.
Open the Series dialog and run the fill it answers with.